Double dowel bar expansion joint



June 2l, 1938. R, R, RQBERTSON 2,121,303

DOUBLE DOWEL BAR EXPANSION JOINT Filed Sept. 24, `193'? f l. j

JMA/

ROBERT R. ROBERTSON fig/5.

Patented June 21, 1938 l PATENT Ilol-llczlai Robert R. Robertson,

The Translode Joint Company, Heights, Ill., a-corporation of Illinois DOWEL BAR, EXPANSION JOINT Chicago, Ill., assigner to Chicago Application September 24, 1937, Serial N0f165,439

The present invention pertains to road joints and more particularly to an improved type oi` road expansion joint adapted to be embedded be-` tween adjacent concrete road slabs, said joint ,including vin combination a precast plastic filler board adapted to be supported upon a road subgrade andhaving openings provided therein at spaced intervals for the reception of adjustable load transmission units, each of which consists of overlapping dowel bars,-the outer ends of which are formed to be anchored' in the adjacent road slabs while the'inner ends ofthe dowel A j.

barsproject in opposite directions through an opening of the ller board and into pockets or housings forming part of flanged supporting plates engaged on opposite sides of the filler board with the flanged portions of the plates resting upon the road sub-grade and staked thereto.

- It is an object of this invention to provide a road expansion joint" comprising a preformedl plastic ller board having openings provided at spaced intervals throughout the length thereof for the reception of slidably overlapping double f dowel bars, carried in supports on opposite sides of the filler board and anchored in the adjacent road slabs for the transmission of loads from one road slab through the joint to an adjacent road slab.

It is also an object of this invention to provide 7 a road expansion joint including a preformed illerboard having openings therein to permit a plurality of sets of slidably overlapping double dowel bars to project therethrough, with the outer ends of each set of the dowel bars anchored in adjacent road slabs and having the inner ends engaged in protecting pockets forming part ofV supports for the double dowel bars and disposed on opposite sides of the filler board.

Anotherobject of the invention is theprovision of a road expansion joint in which an apertured ller board has a plurality of sets of overlapping dowel bars projecting therethrough with the outer ends of the dowel -bars anchored in adjacent road slabs while the inner ends of the dowel vbars are slidably engaged inpockets provided in the `,road slabs opposite from the slab in which the outer ends of said dowel bars are anchored.

It is an important `object of this invention to provide an improved "concrete road expansion joint mechanism including a preformed plastic filler board having openings provided at spaced intervals therein for the reception of load transmission units, each of which consists of a pair of spaced angle supports positioned on opposite sides of the filler board and providedwith protecting housings affording recesses for the reception of the inner ends of do'wel bars which project in 'slidable overlapping engagement through a filler board opening and have theouter ends thereof formed to provide anchors for anchoring the outer ends of the dowell bars in adjacent road slabs.

O ther and further important objects of this invention will be apparent from 'the disclosures in the specification and the accompanying drawing. l f

The invention, in a preferred form, is illustrated in the drawing and hereinafter more fully described.

On the drawing: Figure 1 is a fragmentary side elevation of an expansion joint forming mechanism embodying the principles of this invention and disclosingr the apertured ller board with spaced load transmitting units engaged therein and showing one of the openings unfilled.

Figure 2 is an enlarged sectional View taken on line II-II of Figure 1 showing the expansion* L' joint forming mechanism embedded in the concrete road slabs and supported on the road sub' grade, and furthermore illustrating one-half of fone of the units in elevation, While the opposite half is in section. Y

Figure is an enlarged vertical detail section taken on line III-III 0f Figure 2. Figure 4 is a fragmentary side elevation of a portion of a modiiied form of road expansion joint load transmission unit wherein the dowel bar supports are provided with modified forms of pockets or housings for the reception of portions of the overlapping dowel bars.

Figure 5 ls a fragmentary transverse detail section taken on line V-V of Figure J4.

` As shown on the drawing: V 'I'he expansion joint, as illustrated in VFigures 1 ,to 3 inclusive is formed by means of joint forming mechanisms adapted to be supported on -a road sub-grade I for embedding between concrete road slabs 2 and 3.

The improved expansion joint forming mechalnism comprises a preformed or precast plastic y y ller board I constructed out of asphalt, sponge 1 rubber, cork, or/any other suitable compressible,

material, such for example as a compressible'maa terial known to the trade as Flexcel". The flller board or core member I is provided with a plurality vof spaced openings 5 for the reception of load transmitting means forming a part of a load transmission unit, one of which is associated with each of the filler board openings 5.

Each of the load transmission units comprises a pair of oppositely positioned metal plates 6 adapted to be' positioned against opposite sides of the filler board 4 adjacent one of the openings 6. Each of the metal plates 6-has integrally formed on the lowei` margin thereof an outwardly projecting base ange 'I which seats upon the top surface of the sub-grade I, as clearly illustrated in Figure 2. -Each of the metal plates 6 has an opening formed therein by striking outwardly a ilange 8. A socket or housing is secured to the outer side of each of the plates 6 in register with the opening in the plate 6 and with one of the openings 5 in the ller board 4. The socket or housing comprises a top plate 9, the side margins of which are deflected to provide side walls I0. One end of the top wall 94 is bent outwardly to provide a mounting flange I I which is spot welded or otherwise rigidly secured to the outer .surface of a plate 6. The outer end of the top plate 9 is deiiected to provide an end wall I2 and a projecting flange I3.

Each of the sockets or housings which are attached to the plate 6 has an open portion opposite the plate 9 which is closed by means of a dowel bar I4 to which the socket or housing flange I3 is spot welded or otherwise rigidly secured. The dowel bar has slidable contact with the plate flange 8 which acts as a guide for the slidable movement of the dowel bar. The outer end of each dowel bar I4 is longitudinally split with the split portions deflected upwardly and downwardly to form anchoring ngers or blades I5. The end portion of each of the dowel barsl opposite the anchoring blades I5 projects through the opening in the plate 6 and through an opening 5 of the iiller board 4 and then through the opening in the opposite plate 6 and into a chamber I6 in the opposite socket or housing. This arrangement, as clearly illustrated in Figure 2,

Y positions the inner end portions of the two dowel bars I4 in slidable overlapping engagement with respect to one another, so that the two dowel bars projectl through an opening 5 of the filler serves to-close an opening in the socket or housing. One end of each of the dowel bars is formed to be anchored in` a concrete road slab while the opposite end of the dowel bar slidably projects through the iiller board .and into a'chamber of the socket or housing of the opposite angle plate.

The expansion joint forming mechanisms, as f illustrated in Figurevlpare adapted to be positioned transversely upon a. road sub-grade I with the double dowel bars of each of the load trans- 'mission units projectingthrough the opening 5 of the ller board 4 and with the base flanges 1 of the plate lG'resting upon the sub-grade and secured in position by means of retaining stakes I1 which project through openings in the base flanges 1 andare driven into the sub-grade I -on diagonally opposite sides of the double dowel bars and onopposite sides of the filler board, as clearly illustrated in Figure 1.

ting the ends of the dowel bars to project in opposite directions and slidably engage in the chambers I6 of the sockets or housings forming parts of the two angle plates 6 which are positioned on opposite sides of the filler board. With the expansion and contraction of the road slabs due to temperature changes, the overlapping dowel bars of the load transmission units are slidably moved in opposite directions through the filler board and the plates 6. The improved expansion joint also is adapted to transmit loads applied to one of the road slabs through the joint mechanisms to the opposite road slab. 'I'he transmission of loads isaccomplished by means of the double dowel bar constructions forming part of the spaced load transmission units associate with the ller board 4. Y

Figures 4 and 5 illustrate a modied form of the load transmission units associated with the apertured filler board.- The modified vform of load transmission unit comprises spaced angle plates I8 having openings therein with the openings of the opposite plates positioned directly opposite one another. Rigidly secured on the outer face of Veach of the angle plates I8 is a socket or housing I8 closed at the top, bottom, and at both sides. Upwardly and downwardly projecting flanges are integrally formed on one end of the housing I9 and are spot welded or otherwise rigidly secured to the outer face of the angle plate I8. Integrally formed on the outer end of each of the housings I9 is an end plate 2I which closes only half of the fouter end of the housing. Inte'grally formed with the end plate 2| is a flange 22 which is spot welded or otherwise rigidly secured to a load transmitting dowel bar 23. The double dowel bars shown in Figure 4 are constructed the same as those illustrated in Figure 2 and have the ends thereof projecting in opposite directions in overlapping engagement with respect to one another to span the space between the angleplates I8 so that the ends of the dowel bars slidably project into the chambers 24 providedin the housings I9.`

It will, of course, be understood that numerous details of construction may be varied through a wide range without departing from the principles .of this invention, and it is, therefore, not the imposed slidable contact with one another and.y

projecting through the openings in said filler board, and housing ineans rigidly secured to each of the dowel bars and embedded in the concrete on opposite sides of the filler board for slidably receiving an end of the other dowel bar.

2. An expansion joint forming mechanism including in combination, a preformed compressible filler board having openings therein at spaced intervals, a plurality of pairs of load -transmission arranged in reverse superimposed slidable contact with one another, apertured angle plates posi-- tioned on opposite sides of the ller board, means for securing the apertured angle plates in position, and housings secured to the outer sides of said angle plates with one of said housings secured to each of said dowel bars and slidably receiving one end of another dowel bar.

3. A road expansion joint comprising a preformed ller board having spaced openings therein, apertured metal plates on` opposite sides of the filler board adjacent the openings, apertured base flanges on said plates for supporting the plates in position upon a road sub-grade, housings secured to said plates over the openings therein, and superimposed contacting loadv transmission dowel bars projecting through said plates and through the filler board, each of said dowel bars secured to one of said housings and slidably projecting into an adjacent housing.

4. An expansion joint forming mechanism including in combination a load transmission unit comprising a pair of spaced plates, a housing rigidly secured on the outer face of each of said plates, a dowel bar secured to each of said housings and having the inner en d thereof projecting through the space .between saidrplates and into an opposite housing in slidable contact with the adjacent dowel bar, and anchoring means formed on the outer ends of said dowel bars. l i

5.*An expansion joint forming mechanism incomprising a pair of spaced apertured angle plates, a housing secured on each of said angle plates and a dowel bar secured to 'each of said housings and projecting through the respective angle plate on which the housing to which it is secured is engaged, said dowel bars being reversed with respect to one another and slidably contacting one another to bridge the space between said angle plates.

6. An expansion joint forming mechanism including in combination a load transmitting unit comprising a pair of reversed apertured angle plates, a housing secured to each of said angle plates, a ange on each of said housings, and a load transmission dowel bar projecting through each plate and housing and rigidly secured to the respective housingange, said dowel bars project,- ing in opposite directions in slidable contact with one another to span the space between the angle plates.

7. In an expansion joint for embedding between adjacent concrete road slabs, a preformed plastic filler board mounted between the road slabs and having openings therein, housing members on opposite sides of the filler board adjacent the openings therein and embedded in said road slabs, and pairs of reverse superimposed load transmission dowel bars embedded in the concrete slabs and projecting through the openings in the filler board, each of said dowel bars being secured to one of the housings and slidably projecting through the filler board into a housing on the opposite side of the joint.

ROBERT R. ROBERTSON.

cluding in combination a load transmission unit 

